This invention relates to mechanisms for controlling the output paper path in an image-forming apparatus, such as an electrophotographic or other printer. More specifically, this invention relates to a linkage between a pivotal housing door and a media-directing member, so that movement of the door between two positions causes the directing member to guide paper or other media into two different paths.
Several prior art image-forming devices, such as computer printers sized for desk-top use, have been provided with two media output trays, typically a face-down media-output tray and a face-up output tray. One of the output trays is typically at the end of a non-straight paper path, in which path the paper makes one or more turns between the print engine and the tray. The other of the output trays is typically at the end of a straight-through paper path, in which path the paper makes little, if any, change of direction between the print engine and the tray. Because paper typically exits the print engine with the printed side up, and the non-straight paper path typically turns the paper over relative to its orientation as it exits the print engine, the tray at the end of the non-straight paper path is a face-down tray. Because the straight-through paper path does not change the orientation of the paper after it exits the print engine, the tray at the end of the straight-through path is a face-up tray.
The face-down output tray is typically at the top of the printer housing, and paper exiting from the print engine curves generally vertically upwards and around about 130-180 degrees to rest face-down in the tray. In the face-down tray, pages stack facing downward in correct order.
The face-up output tray is typically a pivotal housing door in front of the print engine, wherein xe2x80x9cfrontxe2x80x9d is so defined as the general direction of paper travel as it leaves the fusing station of the print engine. The face-up tray is positioned relative to the print engine so that paper moves generally straight forward horizontally from the print engine, with print facing upwards, and straight out of the housing into the face-up tray without any significant turns in its path. In the face-up tray, pages stack face-up in reverse order, with the first-page facing up at the bottom of the stack and the last-page facing up at the top of the stack.
Typically, the housing door is designed to lie smoothly against the printer housing in a generally vertical position when the door is closed. When the door is fully opened, it pivots out and down from the printer housing to rest in the proper position to serve as a paper-receiving tray, which is a generally horizontal position in front of the print engine.
The face-up tray is normally chosen when a user wants a substantially straight-through paper path, to minimize curling of an envelope, transparencies, or postcards, or when a user wants paper to exit and stack face-up. In the past, the face-up tray is selected when the user manually flips a small, tab-style handle or switch on the outside of the housing that is connected to a media-directing member. This way, the user directly controls the media-directing member and may flip it back and forth between its two positions, while keeping track of the directing member""s position by noting the position of the small handle.
The media-directing member is sometimes called a xe2x80x9cvanexe2x80x9d and includes a media-contact surface extending along or spaced along a rotatable shaft, the shaft being transversely disposed to the direction of paper travel. When the manual handle rotates the vane to place the media-contact surface in the way of the advancing media, the typically-curved media-contact surface directs the paper to move in the first, turning path. When the manual handle rotates the vane to move the media-contact surface out of the way, and, optionally, to move a second surface of the vane into the path of the paper, the vane then xe2x80x9cdirectsxe2x80x9d (or allows) the paper into the second, straight-through path. xe2x80x9cAutomaticxe2x80x9d methods of switching the paper path between two paper trays have been designed, as a way to make the switching easier and to make it more evident whether the printer is in face-up or face-down output mode. Several of the methods are shown in U.S. Patents. For example, Chen (U.S. Pat. No. 5,234,213, issued Aug. 10, 19993) discusses two control systems in which manual movement of a housing door automatically changes the paper path, as discussed below.
The system labeled as xe2x80x9cprior artxe2x80x9d in Chen comprises a paper guide with generally triangular members on a shaft. Each triangular member has a concavely-curved hypotenuse surface that serves as a guide to urge paper upwards to a first, upper paper tray at the top of the printer housing. The paper guide has a crank extending radially from the shaft that is biased by a spring into a generally downward position, which causes the hypotenuse surfaces generally to face the oncoming paper from the print engine. When in this biased position, the hypotenuse surfaces are tipped forward and slightly downward, so that the horizontally moving paper abuts into the hypotenuse surfaces and curves upward. A housing door is pivotally installed near, but unattached to, the paper guide. As the door pivots open to a generally horizontal position to act as an output paper tray, a bottom portion of the door pivots toward the crank and impacts the crank near its bottom, pushing the crank and pivoting the paper guide. This rotates the hypotenuse surfaces up to a more horizontal orientation, so that oncoming paper misses the hypotenuse surfaces and instead moves along the bottom of the triangular members, thus, keeping the paper generally horizontal as is moves into the open door tray.
Chen also discloses what Chen considers an improved, gravity-operated paper guide. The gravity-operated paper guide also includes a triangular member on a shaft with a crank, but the crank is so disposed as to affect the gravitational center of the paper guide. The crank is so designed, and the pivotal door so positioned relative to the crank, that, when the door closes, the door impacts the crank and pushes the crank upwards. Pushing the crank upwards in this way rotates the paper guide into the path of the oncoming paper, so that the paper-guiding surface forces the paper upward to the first output tray. Then, when the door opens, the door moves away from the contact with the crank, and the paper guide rotates by gravity out of the paper path. In this rotational position, the paper-guiding surface does not interfere with the paper, so that the paper continues its generally-horizontal travel below the paper guide to slide into the open door paper tray.
Kusumoto et al. (U.S. Pat. No. 4,750,016) discloses a tray and paper guide system, in which a cammed surface on a bottom portion of a pivotal tray cooperates with a paper guide shaft. The paper guide shaft is spring-biased to ride along the cammed surface as the door is pivoted inward (closed) and outward (open), causing the shaft of the paper guide to rotate and move downward into the paper path and upward out of the paper path, respectively.
Kimura et al. (U.S. Pat. No. 5,586,758) discloses a paper tray door system, in which a portion of the door itself serves as the paper guide surface when the door is closed. The door portion has a curved surface that, when the door is closed, is positioned directly in front of the paper discharge rollers, receives the paper and urges the paper upward to turn over the paper. When the door is opened, the curved surface is out of the way of the paper, so that paper continues its generally-horizontal travel into the door tray.
Still, there is a need for an improved system that allows the position of the door tray to control paper path selection. There is a need for such a control system that reliably links the door tray to the paper-directing member, so that the user automatically selects one output tray or the other by opening or closing the door tray. There is a need for such a system that makes it immediately apparent where printed media is being directed, that is, to a face-down tray or to a face-up tray. There is a need to such a system that is simple, durable, and reliable.
The present invention comprises apparatus for actuating a media path-controlling device in an image-forming device to switch to a straight-through operation. The present invention mechanically links a housing door/tray to a media-diverter member in such a way that the pivoting of the door/tray also pivots the media-diverter between two operative positions. Also, the present invention may comprise a method for increasing the certainty and ease with which paper or other media is switched to a straight-through path through a printer.
Objects of the invention include integrally linking a media-diverter to the door/tray, so there is a clear understanding of what exit path the media will take. When the door/tray is open, the media will exit into or near the door/tray. When the door/tray is open, the media will exit elsewhere, typically into the other of two output trays. The door/tray is mechanically linked to the diverter, so that the door/tray actively switches the diverter position, rather than the door/tray passively effecting the diverter. Rather than the door/tray simply moving out of the way of the diverter to allow it to swing from a first position into an alternative position, the door/tray of the present invention controls the diverter to quantitatively and clearly switch the diverter between two positions.
The preferred mechanical linkage includes an elongated linkage member extending between the door/tray and the diverter. The linkage member has connection points at its two opposite ends for moveable connection directly to the door/tray and directly to the diverter. One end of the linkage member has a pivotal connection and the other end of the linkage member has a pivotal and axially-slidable connection (that is, longitudinally slidable, parallel to the longitudinal axis of the linkage member). This way, the linkage member may translate the rotational motion of the door into linear motion of the linkage member and then to rotational motion of the diverter, wherein a given amount of rotation of the door/tray on a hinge surely and smoothly causes a lesser amount of rotation of the diverter.
When the door/tray is swung open, it pulls on the linkage member, which slides axially and slightly pivots relative to the diverter, while the diverter remains substantially motionless in its first position. When the door/tray reaches a certain position in its swing, the preferred linkage member no longer slides relative to the diverter and its further movement pulls the diverter to rotate into a second position. In reverse, when the door/tray is swung closed, the door/tray pushes on the linkage member, which slides axially and pivots slightly relative to the diverter, while the diverter remains substantially motionless in its second position. When the door/tray reaches a certain position in its swing, the preferred linkage member no longer slides relative to the diverter and its further movement pushes the diverter to rotate into the first position.
The preferred linkage member is an elongated, generally straight bar, strip, or rod, which has a pivotal axis at one end for connection to the door/tray, and an elongated recess at the other end for pivotal and slidable connection to the diverter. The elongated recess may be a slot, which extends all the way through the linkage member, or a channel, which may extend part way through the linkage member. In any case, the elongated recess pivotally and axially-slidably receives and retains a portion of the diverter for the desired control of the diverter position.